Process for making lead compounds



Nov. 5, 1929. c. H. BRAsELToN Y PROCESS FOR MAKIG LEAD `COMPOUNDS Filed Deo. 2o', 1920 Fig.;

A/r Kompressor Col/5 confa/n/ny com resa-ea a/r e/ hea/ea 6)/ Wa /e bea Fig 5.

@arbe/- L Patented Nove 5, 1929 CHESTER H. BRASELTON, F NEW YOBKyN. Y. l

PROCESS FOR MAKING LEAD OOHPOUND Application mea namur so, man. serial so. 433,048.-

This invention relatesl to a process of mak- A .urther'object of the invention is to proing lead compounds and more particularly to a proces'svby which white lead and oxides of lead may be rapidly and cheaply made and in which lthe conditions suitable for producing a particularly product or quality of product may be easily and accurately controlled. The value of lead products of thetype mentioned above lies very largely in "certain lo physical characteristics, suchl as color and stance the oldDutch .process of making White.

' lead, yields products of very good quality while `other processes attempting to accom? plish the same result in 'a shorterperiodof time fail to 'produce aA product having the desired qualities. In the manufacture of red leadand other lead oxides, processes are also.

employed which require .considerable 'skill f and labor on the Apart of the operator and which are unnecessarily slow in operation and wasteful of heat, Attempts have made to produce products of suitable lquality byv '30 incre rapid :and more eihc'ient methods, but these processes have heretoforejA failedV to produce roducts of the desired uality owing to a ailureto realize Ithe conditions u n 'which the. production of thegdesired pr uct depends..

Anv object ofthe present invention is to provide a rapid andcc'ien't process of makin" ran vexcel ent quality of lead oxides and 'ther compounds, y l

A further object `of theV invention is .to provide a process of makingv lead yoirides which the 'conditions' governin the de of oxidation and the quality o the prof mzgbe accurately controll A further object of the invention is to provide a rapid and cheap process of making white lead, in which the conditions affecting the quality ofthe productvmay be accurately controlled to produce a product of excellent quality.

opacity, which are governed by slight changes .ing Kthe vlead is'cont'rolled to provide the vide an apparatus by means of which omdes of lead and'white lead may -be rapidly made and in which the conditions governing themaking of the product may bereadily and 'ac-4 curatelycontrolled. y

`f ,With these and other objects in view the invvention consists in the process and apparatus described inthe following specification and defined in the claims. y

` vThe various features of the invention are illustrated in the accompanying drawings in which: y

F ig". 1 is a sectional elevation,taken on line 1-1 of Fig. 3,- of the preferred embodiment 5 ist of an apparatus suitable for carrying on the PTUCSS; Y

F ig. 2 isa sectional elevation of the apparai tus taken online 2-2 of Fig; 1, and

' Fig. 3 is a sectional plan view of a portion 70' of the apparatus, taken on line 3 3 of Fi 1.

- In thiresent invention a body of lead to be trea is maintained at`ap' roximately' a temperature suitable forcarrying on the re'- a'ctin for reducing the product desired, and 75 y air and ot 'er gases for treating the lead are passed, atv a suitable temperature, through the lead in a number of very' line streams or bubbles. The temperature'of the gases enter'- o 0 proper `conditions for the production of the g particular product desired.v ThisV control of the temperatureis obtained by passing the main portion of the air through along heated pipe in. which itis heated to a' temperature somewhat above that requiredin the treatment of the lead and adding to the heated portion of the air, regulated quantities of cooler air to bringlthe temperature. of the resulting mixture to' the desired point. 'To increase the activity of the air, portions of the air supplied may be bypassed through an ozonating device or other appxratus or activating the oxygen of the air, fore ,bringing it into contact with theheated lead. A small amount of steam ma also be added at this point.Y The oxides o ead resulting from the contact of the hot ases'lwith the lead are carried upwardly- ,wit thees'caping air and gases and maybe separated therefrom :by any suitable 100 of lead carbonate and lead hydroxi e necessary to give the products a suicient opacity or covering power. The temperatures of these are also controlled` to permit contact of the gases and of the leadv under oing treatment at a temperature suitable fgor carrying on the reaction and low enough to avoid the decomposition or dissociation of the products produced. To this end, additional quantities ofthe ases may be brought into contact with the lea or with the gases leaving the lead, in order to more accurately control the temperature of the gases during their further contact with the particles of lead or product formed durin the process. 'n l Re erring more particularly to the accompanying drawings, lead to be treatedis supplied rom a melting kettle 10 through a supply pipe 12 to a treating kettle 14, in which it is contacted with air and other gases necessar to form the particular product desired. he treating kettle 14 is positioned within a' furnace 16 and is maintained at a desired temperature, by means of a fluid fuel burner 18 ositioned in the l-'ower part of the furnace. e temperature of the lead in the kettle 14 may be controlled by regulating the quantity of uel supplied through the burner 18, or b by-passing a portion of the hotproducts o combustion through an opening` 20 leading directly to a waste heat chamber 22.

The quantity of'hot gases by-passed through the opening 2O may be controlled by means of a damper 24 in such a manner that when the damper 24 is closed the gases are compelled to pass under the bottom ofthe kettle 14 and to circulate around the upper-walls of the kettle before passing tb the Vdhamber 22.

Airifor oxidizing the lead in the kettle 12 is supplied by meansof, a compressory 26 through an air supply main 28 and branch pipe 30 to a coil of pipe or a number of coils 32 positioned in the waste chamber 22. The quantity of air'supplied to the heating coils 32 is controlled by means of a valve 34 in the branch pipe 30. The hot products of combustion supplied to the chamber 22 from the furnace 16 are causedto pass back and forth over the heatingcoils 32 in a comparatively long path by means of a number of baliles 36, '38 and 40, thus causing a thorough contact of the gases with the coils and thereby obtaining a maximum absorption of heat from the heating gases. vFrom the coil 32 the heated air passes to a second coil or set of coils 42, ositioned in a heating chamber 44 imme iately above the chamber 22 and is heated to a still higher temperature by means ofburners 46 positioned in a furnace 48 surrounding the melting kettle 10 and communicatin with the heating chamber v44. In the v cham r 44the air is heated-to a temperature suitable for the treatment of lead or may be raised to a temperature somewhat above that suitable for the treatment. In the latter case the temperature of the air is brought to the desired point before contacting with the lead, by by-passing an additional quantity of cold alr from the supply main 28 to the exit end of the coil 42 through abranch pipe 50 and control valve 52. The" temperature 'of the air leaving the coils 42 is measured by means of a therniocouple or other suitable pyrometric apparatus and the opening of the valves 34 and 52 are adjusted to obtain the y 14. A very large area of Contact between-l the lead and the treating gases and a. correspondingly rapid treatment of the lead vis thereby obtained. Y .f

The activity of the air or oxygen'ma 'be increased by by-passing a portion of air rom the supply main 28 through'a connecting pipe 60 and 'control valve 62 to an ozonating device 64 in which the air passes between lplates 66 alternately charged with electricity of opposite potentials by means. of a step-up, trans- :former 68. From the ozonator 64 the ozonated or highly activated ox gen passes through a pipe O and a contro valve 72 to the pipe 56 and is mixed with the hot air just prior to the entrance of the latter into the distributor 58. By meansof the valves 34, 52 and 62 the temperature and relative proportions o air or oxygen andA ozone may be controlled to maintain the proper temperature conditions for' obtaining any desired degree ofoxidation. A small quantity of steam may also be admitted from a steam generator 7 4 and a steam pipe 76, the quantit admitted being controlled by a control va ve 78. The oxides of lead produced by the action of the hot air and ozone or activated oxygen are carried to the surface of the molten lead by the upwardly passing bubbles of gas. A portion ofthe oxides may be rojected above the surface of the lead and) carried along with the hot gases while the remainder may precipitator orl other suitable separatin means, not shown, in which the suspende particles may be separated from the gases.

hat portion of the oxides which accumulates on the surface of the molten lead flows over the upper edge of the -kettle into an inclined conduit 82 and is removed. e.

When white lead isdesired instead ofjlead Y oxides the quantity of steam supplied through the pipe 76 is increased by opening the valve 78 and av supply of carbon dioxide is also added to the gases entering the pipe 56. rllhe carbon dioxi e for this purpose may be supplied from any, suitable source. In the apparatus'shown in the accompanyin drawings, the supply of carbon dioxide is ta en from a iiue or stack 84`receivin the waste products of combustion from the eating chambers 22 and 44. For thisv purpose a stream of carbon dioxide is continuouslydrawnfrom the stack 84 through a pipe 86 and purifier 88 by means of Ya blower or air pump 90 and forced through a connecting pi e 92 and control valve 94 into the ipe 56. nk the uriiier 88 the carbon dioxide is carefully filtered and uriiied of gases which might injure the pr uct. The

roportions of air, ozone, steam and 'carbon ioxide are carefully controlled by the valves 54, 72, 78 and 94 to provide the required quantities .of the Vvarious reagents'to form the roper proportions of the lead carbonate lead ydroxlde in the product. The carbonatos and lead hydroxides are normally in the proo rtion of 2 molecular weights of lead car- Bonate to one molecular weight of lead hyl droxide. f 4' The tem erature. ofthe gases is also controlled to Ibringy the resulting temperature ofthe vmolten lead in the kettle 14, as near as possible to a point involvin the minimum decom osition of the p ucts 'proudced Lead ydroxide decomposes at a compares tively low temperature and it is desirable, to surround the particles of white lead during cooling with an atmosphere containing the proper amounts of steam and carbon dioxide.-

Additional quantities of air, ozone, carbon To this end a portion of dioxideand' steam are therefore supplied to the' space immediately above the molten lead` and brought into intimate contact with the converted or partly converted lead reaching the surface of the mass of molten lead.- ses passing from the coil 42, pipes 70, 92 an 76 are withdrawn through pipes 96, 98, 100 and 102 respectively, and admitted through a manifold 104, Figi-3, to a nozzle or series of nozzles 106, positioned a short distance above the surface of the lead in the kettle 14. The quantities of the dilerent gases-sup liedlthrough the pipes 96 to 102 are control ed by valves 107, 108, 109 and '110Yrespectively, to provide the proper roportions of the various ractin ases. connectin collar 112 is provided etween the lmanifol 104 and the nozzles 106,

in such a manner that the nozzle may be turned about the axis of the manifold 104 by means of a shaft 114 and a crank 116 projecting outside of the furnace walls, to project thet gases atk any desiredangle against the surface of the lead or the particles which are projected upwardly above. the surface of the lead. The temperature 'of the gases introduced in this manner may, of course, be regulated so that when mixed with products emerging from the lead, the proper temperature for carryin on the reaction without a decomposition 0% the White lead being produced will be obtained. p

The treatment of the lead is, however carried on principally in the kettle 14, the additional supply of gases above f the surface of the lead being principally for the purpose of increasing the time of reaction in case the treatment of the lead is not completed in the kettle 14, and to permit a controlled and morerapid cooling of the products carried above the surface of the lead. To maintain the conditions in the kettle 14 constant and to insure a clean separation of ,oxides and other products from the surface of the lead,

the lead is maintained at a substantially'constant level. To this end, the passage of molten lead from the melting kettle 10, thru the outlet 12, is controlled by means of a valve 118, mounted on a lever 120, the position of which is governed by means of a oat 122 as shown diagrammatically in Fig.. 2. Any

other suitable means for controlling the level of the lead may, of course, beemployed.. A feed opening 124 is provided in the top of the furnace 48, immediately above the melting kettle 10 for adding of additional supplies of lead. i

. The heat for melting the lead in the kettle 10 is supplied by ing to the heating chamber 44. Ordinarily the greater portion of the iam'e from the burners 46 passes thru a passage 126 directly to the heating chamber 44, but a portion of these gases may be forced to travel around the kettle 10 by partly closing a damper y128 in the opening 126. A. partition 130 is provided between the chamber 44 and the space above the kettle 14 to prevent the admission of the furnace gases to the oxidized andv the burners-46 before pass-y .llt

which comprises lmaintaining. a mass` of Havingv describedlthe invention, what is claimed as new is:

-1. A. process of making oxides of lead which comprises maintaining a mass of molten lead ata high temperature, assing through said lejad a mixtureofair an ozone and controllingl theA quantities and temperatures'v of said air and ozone to control the degree ofoxidation of said lead. 1

2. A process of making oxides voflead molten lead at a high temperature, passing through saidv molten lead a mixture of air, ozone and steam and controlling quantities and temperatures of said gases to ycontrol the degree of oxidation of said lead. Y

1.3. A process of making voxides of lead which-comprises maintaining la mass of molten. leadv at a high temperature, heating a current 'of air, passing said air into said lead' in the presence of ozone and controlling the proportions of airv and ozone-and the temperature .of said air to control the degree of oxidation of saidlead. f

4. A process of making oxides of lead which comprises maintaining a mass of moltenlead at a high temperature, heatin a currentof air and passin said air throng said lead in the presence o ozone.

5. A process of making oxides vo'flead which comprises maintaining a mass of molten lead lat a high temperature;A passi into said lead a mixture o f heated. air an ozone and'brin g additicnal uantities of air Aand ozone into contactv wit surface of said lead.-

6..A process of l which comprises maintaining a mass oi molten lead at a high temperature passing* 'into said lead a mixture o ozoneand bringin additional quantities of,

air into contact withsa'id lead at the upper air, steam an surface of said lead.

7. A process oi' making oxides of lead.

' molten lead at a high temperature and passin throu'gli said lead a'number of finely divi ed streams of vmixed air and ozone, and

controlling the relative proportions oi air andl ozonetofcontrol the oxidation of said lea `l0. A process of making oxidesv of lead which comprises maintaining leadat a high temperature, passing through said lead a mixture of airand ozone and controlling the upperA making oxides of lead the relative proportions of said air and ozone.

1 1. A process of making oxides of lead which comprises maintaining a mass of molten lead at a high tem erature and pass'- ing through said molten ead a mixture of air, ozone and steam and controlling the propotZ-ios and temperatures of said gases.

process of making oxides of. lead which comprises maintaining a mass' of' molten lead at a hi h temperature, heating rent of air addition quantities of air and ozone and `said lead. I

13. The process ol. manufacturing lead 'compounds which comprises lintimately associating an' oxidizing gaseousmixture with molten leadand intermingling with the evolvedv products arising from the. molten` lead a gaseous mixture of reactive composiv tion; f 14. The process of manufacturinglead passing said air-mixture through.

compounds which comprises intimately as? sociating an oxidizing gaseous mixture with molten lead and intermingling with .the

evolved product a gaseousmixture having oxidizing characteristics. f v

15. The process of manufacturing lead compounds which comprises intimatelyfasvsociating an oxidizing gaseous mixture with` molten lead andcontrol1ing the rate of cool;

ing of .the evolved products.'

, 16. The proce of lanufactui-iiigl leadv compoundsvwhich comprises intimately as. sociating anoxidizing gaseousmixture including air and steam with molten lead and intermingling withthe' products evolved reactive "composition,

from the molten leada gaseous mixture of 'f 1?.'The process of manufacturing lead compounds which comprises intimately associating an `oxidizing gaseous mixtureiib cliidng air and steamwith molten lead,'and

intermingling" with the" products; evolved from the molten lead a 'gaseous mixture of reactive com osition and regulating the temperature lof t e said reactive com Asition.

ilo

18.; In the-manufacture of oxidic lead'com I pounds,'that step which comprises associating a gaseous composition with molten lead, said composition includingozone.

' In testimony. whereof. I ax'my signature vCHESTER H.' BRASELTON.

e a current of au; ad ing to said heated cur- 

